Is Breathing Smoggy Air Hardening Your Arteries?

Breathing particulate-laden (aka smoggy) air may be hardening your arteries faster than normal, according to research published today in PLOS Medicine. While everyones’ arteries harden gradually with age, a team of researchers led by epidemiologist Sara Adar of the University of Michigan School of Public Health discovered that higher concentrations of fine particulate air pollution were linked to a faster thickening of the inner two layers of the carotid artery.

Because the carotid artery feeds blood to the neck, head, and brain, a narrowing or blockage there can trigger strokes. And general atherosclerosis, or hardening of the arteries, is a major risk factor for cardiovascular disease, heart attack, and heart failure.

Past research has demonstrated that the rates of stroke and heart attack are higher in polluted areas, but experts haven’t been able to pinpoint just how polluted air is raising peoples’ risk for heart attack or stroke. This time, Adar’s team, along with Joel Kaufman, professor of environmental and occupational health sciences and medicine at the University of Washington,was able to directly measure carotid artery thickness and link it to air pollution data.

The study involved 5,362 people between the ages of 45 and 84 living in six different cities that are part of the MESA AIR (Multi-Ethnic Study of Atherosclerosis and Air Pollution) research project, led by Joel Kaufman. Each participant underwent two carotid artery ultrasounds three years apart. These measurements were then correlated with data on fine particulate air pollution.

While the artery walls of all participants increased by 14 micrometers per year, the arteries of those who were exposed to higher levels of fine particulate air pollution in their homes thickened faster than their neighbors in other parts of the city. (Data were adjusted for confounding factors such as smoking.)

Which Cities Were Sampled?

So far, the MESA AIR research project has six field site sampling stations in: